


You belong with me

by swallowthewhale



Series: Killervibe Week [17]
Category: The Flash (TV 2014)
Genre: Alternate Universe - Fringe Fusion, Doppelganger, F/M, Killervibe Week, Killervibe Week 2019
Language: English
Status: Completed
Published: 2019-08-28
Updated: 2019-08-28
Packaged: 2020-09-25 04:33:42
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,372
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20370751
Author URL: https://archiveofourown.org/users/swallowthewhale/pseuds/swallowthewhale
Summary: Cisco and Caitlin confess their feelings for each other on the other side. When they come back, they have to deal with the aftermath. A Fringe AU.Killervibe Week 2019: Doppelgängers





	You belong with me

_ The Other Side _

“Cisco,” Caitlin says. “You don’t belong here.”

“No,” Cisco agrees. “I don’t belong here.” He pauses, looking away from Caitlin’s imploring gaze. “But I don’t belong there, either.”

“Yes, you do,” Caitlin whispers. She takes a step forward. “I have thought of a hundred reasons why you should come back. To fight metas, to help Barry, to- to save the world. But in the end, you have to come back.” Caitlin smiles waveringly. “Because you belong with me.”

Caitlin moves closer again, resting a tentative hand on Cisco’s chest. They both lean in, Caitlin slipping her hand around his neck, Cisco holding her around the waist.

Cisco’s eyes flutter open. The room is soaked with the morning sunlight and he smiles at the memory. It’s been a month, but he still thinks it was all a dream sometimes. Cisco was going to stay on the other side, where he was kidnapped from as a child, to get to know his father. Caitlin had been the one to figure out that his father was lying, trying to get him to stay so he could exploit Cisco’s powers. Caitlin was the one to bring him home.

Rolling over, he wraps around Caitlin from behind, burying his nose in the back of her neck.

She sighs contently, leaning back into him.

“Morning,” Cisco mumbles.

“Morning,” Caitlin says, moving to turn when both of their phones buzz.

They both groan, collapsing into each other for a moment before answering the phones.

It seems to be a home robbery gone wrong, for all intents and purposes, except for the white eyes, bloody noses, and no obvious cause of death. Caitlin brings the bodies back to Star Labs for autopsies while Barry goes over the crime scene and Cisco tries to ID the men.

“Hey, Iris.” Cisco waves Iris over from the other side of the cortex to his screen. “Check this out.”

“Huh,” Iris says, looking over his shoulder. “They’re brothers?”

“Triplets,” Cisco says, pulling up their birth certificates.

“Cisco,” Iris says dryly. “Triplets means three. We only have two.”

“Yeah,” Cisco says, pointing a Twizzler at her. “That’s because the third is still alive.”

Iris raises an eyebrow. “You think he was involved?”

Cisco brings up an old Central City Chronicle article. “Probably, since they’ve got a history of robbing places together.”

Iris sits at the other monitor. “Let’s track this third brother down, then.”

The third brother, Dan, seems to be in hiding. He doesn’t have an address, a job, or any property in his name. Joe puts out a BOLO and Cisco puts Dan’s face into his facial recognition program. They’re just eating lunch when Cisco gets a ping on the meta alert app.

“Uh oh,” he says, swiping through the reports. “We found our missing brother. He’s a meta.”

Barry zips out of the room and returns in his Flash disguise. “Where?”

“Hold your horses,” Cisco says, pulling up live footage of chaos at what looks like a subway station. “We need to figure out a way to neutralize his powers first. Caitlin?”

Caitlin walks in from the hallway, drying her hands on a paper towel. “Some kind of ultrasonic sound wave. Usually it just messes up the inner ear and may cause hearing problems, but it seems like he’s able to emit such intense sound waves that they can basically cause your brain to explode.” She levels Barry with a firm look. “No amount of speed will help if your brain is goo.”

Cisco groans. “Well, I guess we’ll brainstorm on the way. Barry, you get as many people out as you can. Caitlin and I will think of something.”

Barry takes off and Iris hands Cisco a pair of power dampening cuffs. “Good luck,” she says.

“Thanks,” Cisco says wryly, offering a hand to Caitlin as he opens a breach. “We’ll need it.”

“Normal ways of cancelling sound won’t work,” Cisco says as they search the crowd for the brother. “Any ideas?”

Caitlin shakes her head, spotting Joe and nudging Cisco. They meet Joe by the stairs.

“He’s on the tracks,” Joe says grimly. “Seems like he’s waiting for a train to come in before he hits.”

“That makes no sense,” Cisco mutters as they go down the stairs to the tracks. “There’s way more people up here.”

Caitlin shakes her head. “It doesn’t matter.” She turns to Joe and holds out her hand. “I need your gun.”

Joe’s eyebrows go up. “Excuse me?”

Impatiently, Caitlin explains. “I’m going to shoot it next to Cisco’s ears. He’ll basically be deaf and it’ll give him about sixty seconds to find our meta and get the cuffs on him. If anything goes wrong, he can breach out.”

Joe looks skeptical, but at Cisco’s nod, hands Caitlin the gun.

Caitlin faces Cisco, breathing deeply. “Set your watch,” she says. “You don’t have long. And the sound will be amplified by the tunnel. You can’t survive that.”

Cisco sets the timer on his watch for fifty seconds. He won’t hear it, but he’ll feel it buzz. 

“Ready?” Caitlin asks.

Cisco nods.

After the two loud cracks, everything subdues to a buzzy, quiet world. Cisco gives Caitlin a thumbs up and makes his way into the tunnel.

Dan is hilariously easy to take down. Cisco gets the cuffs on him before his timer buzzes and starts shoving him back toward the platform when something slams into him, knocking both him and Dan into a crevice in the wall. Cisco opens his mouth to shout at whoever it was when he’s knocked back again, this time by the incoming train roaring by. His hearing is coming back.

Cisco looks down to see Caitlin pressed against him. “You saved me,” Cisco shouts.

Caitlin laughs, giddy with relief, and kisses him.

Cisco breaches Caitlin home after Dan has been safely locked up in the meta holding facility.

“So,” he says, leaning against the doorframe. “How much does saving someone run nowadays?”

Caitlin smirks up at him, curling her hands into his shirt and tugging. “I think we can come to an agreement,” she murmurs against his mouth.

Cisco grins, lifting her by the waist and kicking the door closed. “Sounds expensive.”

Late that night, in bed with Caitlin dozing against his shoulder, and _Casa Blanca_ playing in the background on the TV, Cisco’s phone buzzes.

He checks the screen, frowning at the unknown number, and kisses Caitlin’s head, gently pushing her off of him.

“Hello.”

“Is this Cisco Ramon?” A woman asks.

Cisco hesitates. “Yes.”

“I’m calling from New York,” she says, voice a little frantic. “I know this is gonna sound crazy, but I just saw a woman disappear in front of my eyes.”

A heavy sick feeling settles in the pit of his stomach. “Who is this?”

“Her name was Caitlin,” the woman continues. “She has a message for you. She’s trapped in the other universe.”

* * *

_ Entrada _

Cisco tosses and turns all night and in the morning over breakfast, Caitlin asks, “You okay? Seems like you didn’t sleep well.”

“Just some weird dreams.” Cisco takes a sip of his orange juice, then as casually as he can manage, he asks, “Hey, do you remember the first time I went to the other side?”

“Mmhmm,” Caitlin says, not looking up from the toast she’s buttering.

“Did you ever read that letter I gave to you for my parents?”

Caitlin’s movements slow and she flashes him a quick smile. “Of course not. It was private, wasn’t it?”

“Of course,” Cisco says, smiling faintly. He finishes his juice, stomach churning.

“She read the letter, didn’t she?” Caitlin says quietly.

Cisco looks up into the barrel of a gun.

Other-Caitlin motions with it to the kitchen chair. He sits. “Yes. She told me when I got back that I should tell my parents what I put in the letter in person. Try to fix things with them.”

Other-Caitlin reaches into her bag one-handed while still holding the gun up. “How’d you figure me out? It had something to do with that phone call you got last night, didn’t it.”

Cisco doesn’t want to admit that he’d needed help to realize she wasn’t his Caitlin. “How did you do it? How did you replace Caitlin? You were with us when we came back from the other side, weren’t you?”

Other-Caitlin steps closer, lips pursed in a terse smile. “I know you have a lot of questions. But I can’t give you the answers.”

“I guess answers are where you draw the line,” Cisco says sardonically.

She tosses him the pouch she pulled from her bag.

Cisco opens it to see a syringe and a little bottle. “Is this gonna kill me?”

“Not if you do it right,” Other-Caitlin says calmly. “Five CCs.”

Cisco uncaps the needle. “So why are you here? What was your plan?”

Other-Caitlin doesn’t answer, just watches him fill the syringe, gun hand still steady.

He smiles grimly. “Yeah, I wouldn’t tell me either. Because if this doesn’t kill me, the last thing you want me to have is information.”

“Are you gonna come after me?” Other-Caitlin asks slyly. “Are you gonna kill me?”

“I’m gonna get answers,” Cisco says, staring her down steely-eyed. “And if I find out that you did anything to Caitlin, _then_ I’m gonna kill you.” He doesn’t wait for a response, injecting the serum into his arm without flinching.

Caitlin would be proud. Other-Caitlin lowers the gun slowly with an unreadable expression as his vision goes blurry and his body seizes up.

Cisco watches as she gathers some things into her bag and leaves. Then he waits. Some hours later, he calls Barry. He feels amazingly calm about everything. Maybe Other-Caitlin had put a sedative in there, too. He’s certain they’ll catch her.

Iris is the one who figures out that Other-Caitlin had taken the wrong bag in her haste, and they find a piece of paper with an address and a code. The address is a phone booth and the code unlocks a secret back panel which reveals a sleek, futuristic-looking device that Cisco eventually figures out is some kind of inter-universe communication device. With Barry’s help, they find the last message received on the device, directions to meet at a train station downtown where Other-Caitlin will be extracted. 

Barry runs them there just in time for Cisco to see Other-Caitlin climb into the back of a truck from across the busy street. He pushes his way across, cursing Barry for suggesting they split up, and watching as a blue light glows from under the van door. When he reaches it and wrenches the door open, it’s empty. Cursing, Cisco slams the door shut again. He kicks it for good measure, and wrenches his phone of his pocket, about to call Barry when Iris’ name pops up on the screen.

“Iris, we lost her,” Cisco steams. “We were too late.”

“Cisco,” Iris says. “Caitlin’s back.”

Cisco is having a hard time focusing on the mystery of the missing heart, too distracted by examining Caitlin, back on a case only days after returning from another universe without much explanation of what happened over there or how she got back. All she would say is that they tried to wipe her memories, but it didn’t stick, and a friend helped her cross back over. She still looks gaunt and tired, but she glares at him every time he asks if she’s sure she’s ready to be back working, so he’s picking his battles.

“I don’t get it,” Caitlin is telling Joe. “These are precise surgical incisions. I doubt it was a black market operation because of how clean the removal was, but what other reason could there be?”

Joe shrugs, seeming as lost for answers as Caitlin is. “Can we send him to the morgue, or do you want to take him to Star Labs?”

Caitlin shakes her head. “Go ahead, there’s nothing much left to see.” She strips off her gloves and follows Joe outside to speak with the Medical Examiner.

Barry elbows Cisco once they leave. “Have you told her?”

Cisco frowns down at his camera, clicking through the photos he took.

“You should be honest with her,” Barry says more gently.

“I will,” Cisco says reluctantly. “Even though I know it’s going to completely change the way she feels about me.”

Barry claps him on the shoulder sympathetically. “You’re a good guy, Cisco. She knows that.”

“We’ve got an ID,” Caitlin calls, coming back into the room. “Grant Russo. Weird thing is, he had heart transplant surgery three months ago.”

They all look at each other. “Well,” Cisco says. “I guess we should go see his doctor.”

Caitlin waits in the cafeteria while Cisco asks the nurses about Russo’s doctor, Dr. Alexandra Ross.

“Dr. Ross is in surgery,” Cisco calls as walks back over.

“Okay,” she says. “We can wait.”

Cisco hands her a coffee, sitting across from her. “I don’t know how you can drink this stuff. I think they let it go stale on purpose.”

Caitlin laughs, sipping from the cup. “You know when you go on vacation and you come back and some things are a revelation? Like coffee,” she holds up her cup, “or my favorite shoes.” Caitlin sighs, mood shifting. “And then, other things are just…” She trails off. “I don’t know. My mail was opened.”

Cisco’s heart sinks. 

“It’s kind of disconcerting knowing that someone else was living your life.”

He rubs his face, closing his eyes in dread.

Caitlin’s wry smile fades. “You okay?”

Cisco swallows, hand dropping into his lap. “There’s something that I have to talk to you about. About her.”

Caitlin nods uncertainly, wrapping her hands around her paper coffee cup.

He gestures uselessly, unsure how to start. “I noticed…” he hesitates, “changes. Small changes, but definitely there. She’s much quicker with a smile, less… I don’t know, less intense maybe.”

Caitlin tips her head, pressing her lips together in a way Cisco knows means she’s hurt but doesn’t want to show it.

He goes on, trying to make her understand. “She said that when she was over there, when she saw her other life, it made her want to change, to be happier. And I believed her, because that made sense.”

“There was no way for you to know,” Caitlin says quickly. “Everything happened so fast, I don’t even know how they did it.” She shrugs a little. “It’s okay. I’m here now.”

Cisco shifts, looking away. “Caitlin, when you asked me to come back with you, you said-”

“That you belonged with me,” Caitlin finishes, smiling shyly.

Cisco nods. “And so I can back for you. For us.”

Her smile fades, giving way to devastating understanding.

“And we started seeing each other. And I explained away the differences because our relationship was different.” Cisco shakes his head ruefully. “I thought she was you, Caitlin.”

Caitlin’s face is frozen in half-hidden heartbreak. She blinks. “Does everyone know?”

Cisco nods slowly, leaning forward. “Caitlin, I’m sorry.”

She shakes her head and pulls away. “You know, I- I can understand how-”

“Mr. Ramon?” A nurse interrupts. “Dr. Ross can see you now.”

“Can you give us a second, please?” Cisco asks the nurse. She nods and turns away.

Caitlin shakes her head, pulling away. “Cisco, it’s fine.” She gives him a tiny fake smile. “We’re good, let’s go.” She stands and starts to follow the nurse.

Cisco watches her for a moment before standing. They’re not good, and it’s not fine. Cisco hadn’t been able to tell Caitlin from Other-Caitlin before, but there’s no mistaking her distress now.

Russo’s doctor isn’t a huge help, except to say he’d received a heart transplant, but while they’re driving back to Star Labs, Joe calls. He’d found dozens of similar incidents, all matching the the missing heart victim but with different organs taken. And all the stolen organs were from the same organ donor; Amanda Walsh. At Star Labs, Iris and Barry are already deep in the files of potential suspects. Cisco and Caitlin join in the efforts, eventually finding Roland David Barrett, an animal researcher who dropped out of Amanda’s therapy group the day she committed suicide. Cisco and Caitlin breach to his house while Barry and Iris check out his office.

It’s clear Barrett is home, they can hear him moving around in the basement. They creep down the stairs, sending a message to Joe and Barry, to see Barrett leaning over the Frankenstein-ed body of a girl. Barrett finishes the last stitch, then puts his hands on her chest as if he was putting defibrillator paddles on her. Tiny sparks jump around his hands and the girl jolts. He tries again, and this time her chest expands and her eyes open.

Barrett smiles, smoothing back her hair. Amanda stares up at him blankly.

“Amanda? Amanda, it's me. It- it's me, Roland. You- you made a terrible mistake. But it's okay now. You're back. It's okay. Hey, hey. Hey, look at me. Look at me. Oh. Oh, no.”

“CCPD!” A voice shouts from upstairs.

Barrett backs away from Amanda, sobbing. 

Caitlin moves forward quickly, snapping power dampening cuffs on his wrists.

“Her eyes,” Barrett whispers. “When I looked into her eyes…” he looks at Caitlin, horrified. “It’s not Amanda. I don't know what I brought back, but I know... it- it wasn't her.”

Caitlin hands him off to Joe and checks on Amanda, pressing her fingers to her neck to find a pulse.

“Is she alive?” Joe asks.

Caitlin shakes her head, gently closing Amanda’s eyes.

Cisco loses track of Caitlin in the chaos of CCPD closing off and starting the inspection on Barrett’s house. He looks around, finally finding Caitlin in the garden, sitting with her elbows on her knees and her hands folded over her mouth.

“Caitlin,” he says, walking up to her, and she presses both of her hands over her face. “You okay?” He touches a hand to her back, stomach sinking when she flinches.

Cisco sits slowly in the chair opposite hers. She still doesn’t move her hands.

“What’s wrong?”

Caitlin shakes her head slightly, rubbing her hands across damp cheeks and finally looking up. “You know what Barrett said? He said that he looked into her eyes and he knew that it wasn’t her.

“Caitlin.”

Her face crumples and she leans back into the chair. “I understand the facts. I know that she had information about me, about my life, and about the people that are close to me.”

Cisco shifts back in his chair.

Caitlin continues on. “And I understand that if she slipped up that she would have a completely reasonable explanation for it. And I guess to expect you to have seen past that is asking too much. But when I was over there, I thought about you, even though I couldn’t remember who you were.” Caitlin pauses, gaze boring into Cisco. “And I held on to you, even though it wasn’t logical and it wasn’t reasonable, I did it. So,” her voice breaks, “why didn’t you?”

Cisco doesn’t know what to say.

“She wasn’t me,” Caitlin says, brow furrowed in pain. “How could you not see that?” Caitlin’s voice wavers with held back tears. “Now she’s everywhere. She’s in my house, my job, my _bed_.” She plucks at the fabric of her shirt. “And I don’t want to wear my clothes anymore, and I don’t want to live in my apartment, and I don’t want to be with you.”

Caitlin swallows, brushing at tears that never fell, then throws up her hands.

“She’s taken everything,” she whispers, standing and walking away.

Cisco watches her leave, then closes his eyes and says, “I’m sorry,” to the empty yard.

* * *

_6B_

Apparently when six people fall to their death off a very sturdy balcony, patio furniture and all, the obvious answer is ghosts. Or that’s what the residents of the Rosencrantz apartment building think, those few of them that are left, anyway. According to the landlord, mysterious things have been happening for the past two months; water pipes exploding just days after having been replaced, the electricity going on and off for no reason, odd sounds.

Cisco and Caitlin stake out the apartment building from the bar across the street for the night, waiting to see if something else happens, while Barry and Iris track down the old tenants who have left. 

Caitlin fiddles with her glass for a while, staring studiously across the street, until she finally breaks the silence. “You know what you said yesterday... what it felt like when you thought you were with me? And you said that it was beautiful?”

Cisco remembers. Barry had very awkwardly invited them over for dinner in an obvious attempt to get them to talk. They had talked, but it didn’t go the way Barry had probably hoped. Caitlin is still hurting and slow to trust again. Cisco puts down his glass slowly. “Yeah.”

“I want to know what that feels like,” Caitlin whispers.

“But?”

Caitlin leans over timidly, tipping her chin up to kiss him. But as soon as Cisco presses forward, she pulls away.

“Caitlin?” Cisco reaches out but she ducks out of the way.

“I need some air. I’m sorry.”

Cisco follows her outside. “Caitlin, whatever that was, if you think that this is a mistake-”

He nearly bumps into her when she stops short. “Look,” she says, pointing up at the Rosencrantz building, where just one light is on. “Let’s go check it out.”

The doorman shows them up to apartment 6B, occupied by a Mrs. Alice Merchant who had lived there for forty-five years with her late husband, who had died two months ago. He had lost a coin toss to fix the fuse box and the wiring shorted, killing him instantly.

Alice happily shows them around her little apartment, handing Caitlin a photo of her husband, Derek.

“What do you think is causing all of this weird phenomenon, Mrs. Merchant?” Cisco asks.

“Alice, please.” She takes the photo back from Caitlin. “Oh, well I suppose it must be the ghost,” she replies, setting the photo back on the table. “He’s been visiting every night for the past two months.”

Cisco and Caitlin exchange a glance. “He has?” Caitlin asks. “You’ve seen the ghost?”

“Well, yes,” Alice says. “It’s my husband.”

Cisco and Caitlin argue quietly about the reality of ghosts while Alice flips through her photo album. When the lights flicker suddenly, she sets it down on the table. 

“That’s him,” she says, standing.

Caitlin and Cisco turn slowly to see a man, about Alice’s age, shimmer into view on the other side of the living room. 

He smiles at Alice, reaching out a hand, as the building starts to shake.

Everything clicks suddenly. “Cisco, there’s no balcony on the other side.”

Cisco frowns. “What?”

“This apartment on the other side, it doesn’t have a balcony.” She points at the photos on the wall behind Derek where there had been none before. Alice and Derek with two young girls. “On the other side, Alice lost the coin toss.”

Understanding dawns in his eyes.

Caitlin steps forward to take Alice’s arm. “Alice, what I'm about to tell you is hard to understand, but everything that is happening in this building is because of you. You're the only person that can stop it. But to do that, you need to let him go.”

Alice shakes her head. “I can’t do that.”

“You have to,” Cisco says. “Alice, the man you're seeing, he's not a ghost, and he's not your husband.”

Alice’s mouth trembles. “You’re wrong.”

“He looks like Derek,” Caitlin says, exchanging a frantic look with Cisco as the quake strengthens. “He looks exactly like Derek, but he’s from another place, another world. He lost his wife like you lost Derek, and he thinks you’re his Alice.”

“Alice,” Derek says. “It’s me.”

“I can hear you. Derek, I hear you!” 

“Alice, sweetheart, I miss you.”

Alice steps forward. Caitlin loses her footing as the building shakes.

“Alice,” Caitlin says. “That man is not your husband, you need to let him go!”

“How can you ask me?” Alice cries. “I can't. I can’t!”

Cisco moves in front of her, grasping her shoulders. “You've already had what most of us only dream of. A lifetime with the person you love. What you and Derek had was true and real. And I know that when you have something so real, you'll do anything to keep from losing it. But please, you have to let him go.”

“Alice,” Derek says. “I miss you so much. And the girls miss you.”

Alice’s smile fades. “We never had children,” she says shakily.

Derek frowns. “Of course we did.”

“No,” Alice says firmly, stepping backwards. “I'm not your wife. Your wife is gone. And so is my Derek.”

Derek vanishes and the quakes stop. Alice drops back into her chair, and Cisco and Caitlin leave her with Joe to figure out how to explain in a police report that a meta had managed to summon her dead husband and his entire apartment building from another universe.

Cisco is leaning against his kitchen counter that night, staring pensively at the rum he's swirling around in his glass, when there’s a tentative knock on his door.

Caitlin is on the other side. “Hey.” She offers him a bottle of wine.

“Hey.” Cisco lets her in. “I'll get the glasses.” He sets his rum aside and pours out two glasses of wine. “To disaster narrowly averted,” he says, holding up his glass.

“Or at least postponed.” Caitlin taps her glass against his, but doesn’t drink. “Cisco, what you said to Mrs. Merchant…” She looks up at him shyly. “I want what you want.”

Cisco puts his glass down, moving around the counter to take her hand. “And what is that?”

Caitlin kisses him in response, wrapping her arms around his shoulders as he pulls her in by her waist.

“Are you sure?” Cisco whispers.

Caitlin smiles, stepping away and sliding her hand into his. 

A matching smile creeps onto Cisco’s face as she tugs gently, leading him into the bedroom.

**Author's Note:**

> Fringe is my absolute favorite TV show ever and it's always the first thing that pops in my mind when I read the word "doppelgängers." Why it didn't occur to me sooner to fuse The Flash with Fringe is a mystery...  
This is basically the mechanics of the Fringe world with The Flash's characters, following a condensed version of Fringe's season three.
> 
> Title is NOT from the Taylor Swift song. Get it out of your head. Watch this instead...  
https://www.youtube.com/watch?v=aMu0rVUYBdM


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